#请使用迭代查找一个list中最小和最大值，并返回一个tuple：
from collections import Iterable
def findMinAndMax(L):
    if isinstance(L,Iterable):
        if len(L)>0:
            min = max = L[0]
            for i in L:
                if i < min:
                    min = i
                if i > max:
                    max = i
            return (min,max)
        else:
            return(None,None)
    else:
        return '请输入可迭代的对象'
        
        
# 测试
if findMinAndMax([]) != (None, None):
    print('测试失败!')
elif findMinAndMax([7]) != (7, 7):
    print('测试失败!')
elif findMinAndMax([7, 1]) != (1, 7):
    print('测试失败!')
elif findMinAndMax([7, 1, 3, 9, 5]) != (1, 9):
    print('测试失败!')
else:
    print('测试成功!')
    
print(findMinAndMax((333,12,34)))